John Wardle, Professor of Astrophysics and the Head of the Division of Science, has been playing an integral role in bringing the first-ever image of a black hole to realization. Announced today, the image of the M87 black hole is being hailed as a major scientific breakthrough. Wardle serves on four of the Event Horizon Telescope’s 23 working groups, helps analyze the polarization of the M87 black hole’s radio emissions, and serves on the publication working group. This announcement was made in a series of six papers published in a special issue of The Astrophysical Journal Letters.

Near a black hole, differential rotation of a magnetized accretion disk is thought to produce an instability that amplifies weak magnetic fields, driving accretion and outflow. These magnetic fields would naturally give rise to the observed synchrotron emission in galaxy cores and to the formation of relativistic jets, but no observations to date have been able to resolve the expected horizon-scale magnetic-field structure. The paper reports interferometric observations (made with antennas in Hawaii, California and Arizona) at 1.3-millimeter wavelength that spatially resolve the linearly polarized emission from the Galactic Center supermassive black hole, Sagittarius A*. We have found evidence for partially ordered magnetic fields near the event horizon, on scales of ~6 Schwarzschild radii, and we have detected and localized the intra-hour variability associated with these fields.

The above image is an artist’s impression. With the planned addition of antennas in Mexico, Chile, Europe and the South Pole, the Event Horizon Telescope will be able to make true images with angular resolution of a few tens of microarcseconds.